Compact crimping device

ABSTRACT

Disclosed herein is a method of crimping a prosthetic heart valve using a compact crimping mechanism. The crimping mechanism includes a plurality of jaws configured for coordinated inward movement toward a crimping axis to reduce the size of a crimping iris around a stented valve. A rotating cam wheel acts on the jaws and displaces them inward. An actuation mechanism includes a lead screw, carriage assembly and a linkage to rotate the cam wheel with significant torque.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.17/247,605, filed Dec. 17, 2020, now issued as U.S. Pat. No. 11,523,923,which is a continuation of U.S. application Ser. No. 16/935,044, filedJul. 21, 2020, now issued as U.S. Pat. No. 11,510,794, which is acontinuation of U.S. application Ser. No. 15/630,711, filed Jun. 22,2017, now issued as U.S. Pat. No. 10,716,691, which claims priorityunder 35 U.S.C. § 119 to U.S. Provisional Application No. 62/354,551,filed Jun. 24, 2016, each of which is incorporated herein by referencein its entirety.

FIELD OF THE INVENTION

The present invention relates to a crimping device and, moreparticularly, to a compact device for crimping devices, such as astented prosthetic valve such as a heart valve, from a large diameter toa smaller diameter.

BACKGROUND OF THE INVENTION

A stent is a generally cylindrical prosthesis introduced into a lumen ofa body vessel via a catheterization technique. Stents may beself-expanding or balloon expandable. Balloon-expandable stents aretypically crimped from an initial large diameter to a smaller diameterprior to advancement to a treatment site in the body. Before crimping, aballoon expandable stent is typically placed over an expandable balloonon a catheter shaft. In cases where the stent was manufactured in itsfully crimped diameter, the stent is expanded and then crimped on theballoon. To ensure safety, the crimping process should be performed in asterile environment. Over the years, attempts have been made to crimpthe stent on a balloon during the operation in the sterile field.However, most stents are now “pre-crimped” on a suitable balloon in thefactory and then delivered to the physician ready for use.

One example of a crimping device for stents based on movable jaws isdisclosed in U.S. Pat. No. 6,360,577 to Austin. This crimping deviceuses sloped planes which force jaws to move from an open position to aclosed position. One primary shortcoming is that the length of thesloped plane is given by a whole circle (360°) divided by the number ofactivated jaws. A long-sloped plane is preferable to reducecircumferential resistance or friction forces, but in order to achieve asmooth aperture for crimping the stent a large number of j aws isneeded, which means a shorter sloped plane, less leverage and higherfrictional forces. Therefore, the effectiveness of this type of deviceis substantially limited and may only be practical for stents which havea diameter of 1.5 to 4.0 mm in their expanded size.

In recent years, a variety of prosthetic valves have been developedwherein a valve structure is mounted on a stent and then delivered to atreatment site via a percutaneous catheterization technique. Prostheticvalves are typically much larger in diameter relative to coronarystents. While a typical expanded coronary stent diameter is only 1.5 to4.0 mm, a stented prosthetic valve diameter will typically be in therange of about 19 to 29 mm, at least 5 times larger.

In another difference, coronary stents are stand-alone metallic deviceswhich may be crimped over a balloon prior to packaging. For prostheticvalves, the stent functions as a scaffold to hold a valve structurewhich is typically made of biological materials such as pericardiumvalves or harvested valves. For improved function after deployment, itis often desirable to package such valves in the open (i.e., expanded)state in a preserving solution. Consequently, it is necessary to crimpthe valve in the operation room a few minutes before implantation,therefore precluding pre-crimping by the manufacturer over a balloon.

Due to the unique crimping requirements for stent-based prostheticvalves, it has been found that existing crimping devices configured foruse with coronary stents are not suitable for use stent-based prostheticvalves. In addition, as discussed above, existing crimping mechanismssuffer from a variety of shortcomings which limit their ability to beadapted for use with stent-based prosthetic valves. Due to thedeficiencies associated with existing crimping technology, a newcrimping device was described in co-owned U.S. Pat. No. 6,730,118 toSpenser, et al. and relates to a crimping device that is adapted tocrimp a prosthetic valve as part of the implantation procedure.

Another version of a prosthetic heart valve crimper is marketed byMachine Solutions Inc. of Flagstaff, Ariz. The HV200 is a disposablecrimper that uses multiple pivoting segments to crimp percutaneous heartvalves. The Machine Solutions crimpers are also disclosed in U.S. Pat.Nos. 6,629,350 and 6,925,847, both to Motsenbocker. These crimpingdevices are based on segments which rotate about pivot pins to createradial compression. Unfortunately, the pivoting design tends toconcentrate stress in certain areas of the individual segments, and inthe mechanism for pivoting them. Also, the user must apply significantforce to close the crimper aperture around a relatively largepercutaneous heart valve.

U.S. Pat. No. 7,530,253 discloses a crimping mechanism for prostheticheart valves having linearly moving jaws which has the capacity to crimpa relatively large size valve down to a small delivery size, but is alsorelatively large in size.

Although the heart valve crimping technology available to date providesan improvement over the existing stent crimper technology, it has beenfound that a need still exists for a more effective device. It isdesirable that such a device be capable of crimping a valve from adiameter of about 29 mm to a crimped size of about 6 mm withoutrequiring excessive force and without inducing high mechanical stresseswithin the device. It is also desirable that such a device is simple touse and relatively inexpensive to manufacture. It is also desirable thatsuch a device be sterile and suitable for manual operation in a catheterlab or operating room. The present invention addresses this need.

SUMMARY OF THE INVENTION

The present invention provides a method and apparatus for crimpingexpandable prosthetic heart valves having support frames and stents. Thecrimping mechanism includes a plurality of jaws configured forcoordinated inward movement toward a crimping axis to reduce the size ofa crimping iris around a stented valve. A rotating cam wheel acts on thejaws and displaces them inward. A number of Cartesian guide elementscooperate with the jaws to distribute forces within the crimpingmechanism. The guide elements are located between the crimping jaws andan outer housing and are constrained by the outer housing for movementalong lines that are tangential to a circle centered on the crimpingaxis. The guide elements engage at least some of the crimping jaws whilethe rest are in meshing engagement so as to move in synch. An actuationmechanism includes a lead screw, carriage assembly and a linkage torotate the cam wheel with significant torque.

In one embodiment, a prosthetic valve crimping device capable ofreducing the diameter of an expandable prosthetic stented valvecomprises a plurality of crimping jaws in meshing engagement andcircumferentially arranged around a crimping orifice having a centralcrimping axis, each having inner crimping wedges. A rotating cam wheelacts on the crimping jaws and displaces them generally radially inward,while a stationary outer housing contains the cam wheel and crimpingjaws. Finally, a plurality of guide elements are each constrained byfixed grooves in the outer housing for movement between first and secondpositions along lines that are tangential to a circle around the centralaxis, wherein the guide elements move at least some of the crimping jawsalong the lines such that all of the crimping wedges of the crimpingjaws translate inward along radial lines toward the crimping axis.

In one aspect, the crimping wedges are made of a different material thanthe rest of the crimping jaws. The guide elements may be separateelements from the crimping jaws. Preferably, the guide elements arerigidly coupled to the at least some of the crimping jaws by beingintegrally formed therewith or fastened thereto.

Advantageously, the crimping jaws each comprise an assembly of a pair oftraveling blocks flanking the cam wheel and one of the crimping wedgesthat extends across a central orifice in the cam wheel. The cam wheelmay include two disks having spiral cam slots that act on cams securedto each of the flanking traveling and that extend axially inward intothe cam slots. Also, the cam wheel disks may each have a cam leverprojecting radially outward therefrom that is driven by a carriageassembly on a lead screw. Preferably, a linkage between the cam leversand the carriage assembly increases a torque applied to the cam wheelwhen the carriage assembly reaches opposite ends of the lead screw.

In a second aspect, the present application discloses a prosthetic valvecrimping device capable of reducing the diameter of an expandableprosthetic stented valve. The device has a plurality of crimping jaws inmeshing engagement and circumferentially arranged around a crimpingorifice having a central crimping axis, wherein the crimping jaws eachcomprise an assembly of a pair of spaced apart traveling blocks and aradially inner crimping wedge that extends therebetween. A rotating camwheel acts on the crimping jaws and displaces them generally radiallyinward, the cam wheel including two disks having spiral cam slots thatact on cams secured to each of the flanking traveling blocks and thatextend axially inward into the cam slots. A stationary outer housingcontains the cam wheel and crimping jaws, and a lower actuationmechanism including a lead screw and carriage assembly is coupled torotate the cam wheel. The pair of traveling blocks of at least some ofthe crimping jaws are constrained by fixed grooves in the outer housingfor movement along lines that are tangential to a circle around thecentral axis such that all of the crimping wedges of the crimping jawstranslate inward along radial lines toward the crimping axis.

In the device of the second aspect, the cam wheel disks each may have acam lever projecting radially outward therefrom that is driven by thecarriage assembly on the lead screw via a linkage between the cam leversand the carriage assembly that increases a torque applied to the camwheel when the carriage assembly reaches opposite ends of the leadscrew. Further, a drive motor may be provided to actuate the lead screw.Also, the crimping wedges may be made of a different material than therest of the crimping jaws.

The device of the second aspect may further include a plurality of guideelements which are each constrained by fixed grooves in the outerhousing for movement between first and second positions along lines thatare tangential to a circle around the central axis, the guide elementsmoving at least some of the crimping jaws along the lines such that allof the crimping wedges of the crimping jaws translate inward alongradial lines toward the crimping axis.

In one embodiment, there are half the number of guide elements ascrimping jaws, such that some of the crimping jaws are driven and someare followers. Preferably, the guide elements are rigidly connected tothe traveling blocks of half of the crimping jaws by being integrallyformed therewith or fastened thereto.

In either aspect, each of the guide elements may comprise a rectilinearplate in an irregular diamond shape with four vertices and straightsides therebetween with an indentation on one side adjacent one of thevertices, and when the guide elements are displaced to the secondpositions along the lines, one of the vertices of each fits closelywithin the indentation on the adjacent guide member, and the nestedcontact between all of the guide elements in this manner provides apositive stop on further inward movement of the crimping mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of an exemplary prosthetic heart valvehaving an expandable support frame and a plurality of flexible leafletstherewithin;

FIG. 1B is a side view of the prosthetic heart valve of FIG. 1A crimpedto a reduced diameter around a balloon catheter;

FIGS. 2A and 2B are partially cutaway views of a crimping mechanism ofthe present application in both open and closed crimping jaw positions;

FIG. 3A is an exploded perspective view showing the components of theexemplary crimping mechanism;

FIG. 3B is a partially exploded perspective view of the exemplarycrimping mechanism with a movable crimping jaw combination assembled,while FIG. 3C is a perspective view of an exemplary cam wheel that formsa part of the crimping jaw combination;

FIG. 4 is an elevational view of the central cam wheel that forms a partof the movable crimping jaw combination;

FIGS. 5A and 5B are different perspectives of one of the crimping jawsshowing inner cam followers, and FIG. 5C is an elevational view;

FIG. 6 is a perspective view of the movable crimping jaw combinationincluding the cam wheel, crimping jaws, and a plurality of Cartesianguide elements;

FIGS. 7A and 7B are elevational views of the inner crimping mechanismshowing the central cam wheel and crimping jaws assembled thereon inboth open and closed crimping jaw positions;

FIG. 8 is an elevational view of an inner face of one half of the outerhousing of the exemplary crimping mechanism showing fixed guide channelsthereon;

FIG. 9A is a view of a plurality of the Cartesian guide elementsarranged in space in the same manner as they would be when interactingwith the outer housing of the crimping mechanism of FIG. 8 , while FIG.9B is a perspective view of a single Cartesian guide element;

FIG. 10A is an elevational view of the inner face of the outer housingof the crimping mechanism showing the locations of the guide elementsthereon when in radially outward positions, and FIG. 10B is a similarview showing the guide elements in radially inward positions;

FIGS. 11A and 11B are elevational views similar to FIGS. 7A and 7B andalso showing guide elements interacting with the crimping jaws;

FIGS. 11C and 11D are partial cutaways of FIGS. 11A and 11B showing theinteraction of just one of the guide elements and three of the crimpingjaws;

FIG. 11E isolates a central one of the crimping jaws from FIGS. 11C and11D to show its relative and absolute movements;

FIGS. 12A and 12B are schematic perspective views of an alternativeembodiment of a crimping mechanism of the present application in bothopen and closed crimping jaw positions, much like that of FIGS. 1A-11Ebut with modified guide elements;

FIGS. 13A-13C are several views of a further embodiment of a crimpingmechanism of the present application similar to that shown in FIGS.1A-12B but with fewer guide elements;

FIGS. 14A-14C are partial elevational views of the crimping mechanism ofFIGS. 13A-13C in both open and closed crimping jaw positions;

FIGS. 15A-15B are elevational views of a still further crimpingmechanism of the present application that utilizes a compressiblesleeve, shown in both open and crimped states;

FIGS. 16A-16B are elevational views of the crimping mechanism with acompressible sleeve with a front cover removed to show internalcomponents in the positions of FIGS. 15A and 15B, respectively;

FIG. 17 is an exploded view of the crimping mechanism with acompressible jaw;

FIG. 18 is a cutaway perspective view of the crimping mechanism with acompressible jaw;

FIGS. 19A-19B are cutaway perspective views of the crimping mechanismwith a compressible jaw showing the movement of one compressionassembly;

FIGS. 20A-20C are perspective and cutaway views of a series ofprogressively sized crimping mechanisms each with a compressible jaw;

FIGS. 21A-21B are schematic elevational views of a still furthercrimping mechanism of the present application that utilizes compressiblejaws; and

FIG. 22A is a perspective view of an alternative crimping mechanismhaving a modified actuating mechanism and an outer housing shown inphantom, while FIG. 22B shows the crimping mechanism from a differentperspective and without the outer housing and FIG. 22C shows a number ofinternal components including crimping jaws exploded.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides an improved crimper for stents orprosthetic valves. The particularly advantageous features of the presentcrimper enable reduction in diameter of relatively large stents orprosthetic valves in conjunction with a small sized crimper thatgenerates high crimping forces to result in small final diameters. Thecrimper is especially suited for crimping prosthetic heart valves whichhave expanded diameters significantly larger than most stents currentlyin use. According to Chessa, et al., the Palmaz-Genesis XD stents(Cordis J&J Interventional Systems Co.) are designed for an expansionrange of 10-18 mm, and are considered as either large or extra-largestents (see, Results and Mid-long-term Follow-up of Stent Implantationfor Native and Recurrent Coarctation of the Aorta, European HeartJournal Volume 26, No. 24, Pp. 2728-2732, published online Sep. 26,2005). The most frequently used stents are significantly smaller, in the3-6 mm range. Crimpers for these stents have proved inadequate forreducing in size even larger prosthetic valves, such as the stentedprosthetic heart valves. Conversely, aspects of the present crimper maybe applicable for use in crimping stents as well, although certainfeatures described herein make it particularly well-suited for crimpinglarge diameter stents, stent grafts, and prosthetic valves.

The term “stented valve” as used herein refers to prosthetic valves forimplant, primarily prosthetic heart valves but also conceivably venousvalves and the like. A stented valve has a support frame or stent thatprovides primary structural support in its expanded state. Such supportframes are typically tubular when expanded, and may be expanded using aballoon or due to their own inherent elasticity (i.e., self-expanding)or by mechanical means. An exemplary stented valve is illustrated withrespect to FIGS. 1A and 1B, although the present invention may be usefulfor crimping other such prosthetic valves.

FIG. 1A illustrates an exemplary balloon-expandable prosthetic heartvalve 20 having an inflow end 22 and an outflow end 24. The valveincludes an outer stent or support frame 26 supporting a plurality offlexible leaflets 28 within. FIG. 1A shows the valve 20 in its expandedor operational shape, wherein the support frame 26 generally defines atube having a diameter D_(max), and there are three leaflets 28 attachedthereto extending into the cylindrical space defined within to coaptagainst one another. In the exemplary valve 20, three separate leaflets28 are each secured to the support frame 26 and to the other twoleaflets along their lines of juxtaposition, or commissures. Of course,a whole bioprosthetic valve such as a porcine valve could also be used.In this sense, “leaflets” means separate leaflets or the leaflets withina whole xenograft valve.

FIG. 1B shows the valve 20 mounted on a balloon 30 prior to inflation.The crimped outer diameter of the valve 20 is indicated at D_(min). Theballoon 30 typically mounts on the end of a catheter 32 which is guidedto the implant sites over a steerable wire 34.

Further details on the exemplary prosthetic heart valves of a similartype can be found in U.S. Pat. No. 6,730,118 and U.S. Patent PublicationNo. 2014/0343671, which are expressly incorporated by reference herein.In addition, the Sapien® line of heart valves available from EdwardsLifesciences of Irvine, Calif. are balloon-expandable prosthetic heartvalves of a similar nature, whose construction is also expresslyincorporated by reference herein.

U.S. Pat. No. 7,530,253 (expressly incorporated by reference herein)discloses a crimping mechanism for prosthetic heart valves which has thecapacity to crimp a relatively large size valve down to a small deliverysize. However, the mechanism in the '253 patent is relatively large dueto the need to create high leverage forces to crimp the large diametervalves. In contrast, the crimper mechanisms disclosed herein createradial jaw motion using Cartesian movement guiding elements, close tothe central aperture. Consequently, the size of the crimping jaws isreduced dramatically and the stiffness (or the ability to withstandhigher crimping forces) of the jaws is increased.

The crimper mechanisms of the present application efficiently reduce thesize of prosthetic valves from up to 30 mm (D_(max)) down to 6 mm(D_(min)). Prosthetic heart valve sizes are typically anywhere between20 mm up to about 30 mm. The minimum reduction in size is thus around 14mm and the maximum around 24 mm. In contrast, typical coronary stentshave an expanded diameter of between about 3-6 mm and are crimped downto a minimum diameter of between about 1.5-2 mm, for a total maximumsize reduction of around 4 mm. To distinguish conventional stentcrimpers, the present invention provides a diameter reduction of atleast 10 mm, and preferably at least 20 mm. Because diametricallyopposed jaws act toward each other to reduce the size of the prostheticvalves, each crimp the valve half the distance of the entire reductionin diameter. This means each jaw moves radially inward at least 5 mm,and more preferably at least 10 mm.

With reference now to FIGS. 2A and 2B, one preferred embodiment of animproved prosthetic heart valve crimping mechanism 40 is shown. Thecrimping mechanism 40 includes an outer housing 42 enclosing a pluralityof crimping jaws 44 arranged about a central crimping axis 46. As willbe described, there are preferably 12 crimping jaws 44, although othernumbers of jaws are possible. The jaws 44 are initially shown retractedoutward in FIG. 2A so as not to be visible within a receiving orifice 48sized large enough to receive an expanded heart valve 20 such as shownin FIG. 1B. FIG. 2B illustrates the crimping jaws 44 displaced radiallyinward in a coordinated manner to form a crimping iris 50 defined by thecombined inner surfaces of the assembly of jaws. The crimping iris 50has a minimum diameter small enough to completely crimp the heart valve20 onto the balloon 30. Although not shown, the crimping operationinvolves placing the expanded heart valve 20 around the balloon 30before inserting the assembly into the orifice 48 and actuating thecrimping jaws 44.

A lower portion of the outer housing 42 is cut away in both FIGS. 2A and2B to expose a portion of an actuating mechanism therein. In particular,a relatively large diameter horizontally oriented lead screw 52 isjournaled for rotation on either side of the housing 42 andperpendicular to the crimping axis 46. Although not shown, a motor inthe lower part of the housing 42 is desirably connected via a powertransmission to drive the lead screw 52 and increase applied forces.Alternatively, one or both ends of the lead screw 52 projects outwardfrom the housing 42 and terminates in a nut or other such keyed element.By inserting a crank or key into one of the ends of the lead screw 52,it may be manually rotated about its axis. An internally threadedcarriage 54 travels back and forth along the lead screw 52 when itrotates. The carriage 54 features a shaft stub 56 projecting from oneside that is retained within a large slot 58 formed in a lever arm 60 ofa cam wheel 62 (see FIGS. 3A and 3B), thus preventing rotation of thecarriage with the lead screw.

Further details of the interaction between the cam wheel 62 and crimpingjaws 44 will be explained more fully below. However, as seen in FIGS. 2Aand 2B, rotation of the lead screw 52 causes the carriage 54 to travelfrom right to left which in turn interacts with the lever arm slot 58and rotates the cam wheel 62 clockwise (CW). Rotation of the cam wheel62 in this manner causes the jaws 44 to be displaced from their radiallyoutward to their radially inward positions, thus crimping the heartvalve 20.

FIG. 3A is an exploded perspective view showing the inner components ofthe exemplary crimping mechanism 40. The outer housing 42 includes twomolded halves that together provide the bearing mounts for the leadscrew 52. Although an inside face of only one of the housing halves isshown, both include a plurality of linear guide channels 64 molded intotheir inner faces and disposed in a spoke-like manner tangentiallyaround the receiving orifices 48. The outer housing 42 halves sandwichtherebetween a crimping jaw assembly 66.

FIG. 3B is a partially exploded perspective view of the crimpingmechanism 20 showing the crimping jaw assembly 66 and one of the halvesof the outer housing 42 with its guide channels 64. The crimping jawassembly 66 has a generally cylindrical profile that fits closely withina similarly-shaped upper portion of the outer housing 42, and iscentered along the crimping axis 46. The crimping jaw assembly 66 ismade up of the moving parts within the crimping mechanism 40, aside fromthe lead screw 52 and carriage 54. With reference also to FIG. 3A, thecrimping jaw assembly 66 comprises an axial sandwich of elements in themiddle of which is the cam wheel 62. The crimping jaws 44 flank the camwheel 62, and a number of Cartesian guide elements 70 are arranged onthe outside of the crimping jaws 44. In turn, the crimping jaw assembly66 is firmly located within the two halves of the housing 42, but mayrotate therein.

To understand the interaction between the moving parts of the crimpingjaw assembly 66, it is necessary to start from the cam wheel 62 and moveaxially outward. The cam wheel 62 is rotated by the lead screw 52 andcarriage 54, and thus forms the prime mover of the crimping jaw assembly66. In general, rotation of the cam wheel 62 initiates movement of allthe other pieces, although as will be described below physicalinteraction and guiding contact between the pieces creates additionalreaction forces that distribute the forces from the cam wheel.

FIG. 3C is a perspective view of the exemplary cam wheel 62, whichincludes a pair of parallel annular discs 72 joined on their innercircular edges by an annular hub 74. A plurality of axially-orientedrollers 76 are journaled for rotation between the two discs 72 andcircumferentially distributed in an annular space 78 defined radiallyoutside of the hub 74. Each of the roller 76 projects slightly outwardfrom the outer edges of the discs 72 so as to contact the outer housing42 to facilitate rotation therein and provide stability to the crimpingoperation. As also seen in FIG. 4 , each of the annular discs 72includes a series of arcuate cam slots 80 formed therein which curvegenerally from their radially inner to their radially outer edges. Eachof the cam slots 80 is curved so as to be radially outwardly convex. Thearcuate cam slots 80 on the two discs 72 are aligned and have the sameshape such that looking at the outer face of one disc the cam slots 80extend radially outward in a clockwise (CW) direction (i.e., FIG. 4 ),while looking at the outer face of the other disc the slots extendradially outward in a counter-clockwise (CCW) direction.

In the illustrated embodiment, there are twelve cam slots 80 nestedrelatively closely to each other around each disc 72. Each two alignedslots 80 in the two discs 72 act on one of the jaws 44, and therefore inthe preferred embodiment there are twelve jaws 44. It should beunderstood that the number of crimping jaws 44, and thus the number ofcam slots 80, may be modified but is preferably between 8-16.

As seen in FIGS. 5A-5C, each of the crimping jaws 44 includes a radiallyinner crimping wedge 82 connecting a pair of axially spaced apart,generally triangular outer traveler blocks 84. The elevational view ofFIG. 5C shows that the traveler blocks 84 each span an included angle θwhich varies depending on how many jaws 44 are utilized, and ispreferably 30° with twelve jaws. When the jaws 44 are assembled alongwith the cam wheel 62, as seen in FIG. 6 with the jaws 44 in theirradially outward positions, the crimping wedges 82 are positioned withina central aperture defined inside the annular hub 74 of the cam wheel62. The inner surfaces of the crimping wedges 82 define theaforementioned iris 50 of the crimping mechanism 40. The traveler blocks84 of each of the jaws 44 closely flank the annular discs 72 of the camwheel 62, and small cam followers 86 extending axially inward from eachof the blocks insert into the arcuate cam slots 80. Each of the camfollowers 86 has a generally rounded configuration and is angled in amanner that aligns with a tangent to the curve of the arcuate cam slots80. The cam followers 86 are sized so as to be slightly smaller than thewidth of the cam slots 80, and may be made of a lubricious material suchas Nylon or Teflon to facilitate sliding therein. The cam followers 86are located at a radially outer extent of each of the traveler blocks84.

At this stage, a further word about materials is relevant. Many of thecomponents are molded of a suitable polymer, such as the outer housing42 and cam wheel 62. The lead screw 52, carriage 54 and of course motorparts will preferably be metallic, though some may also be polymer. Thecrimping jaws 44 may be a molded polymer, though the inner crimpingwedge 82 which contacts the article being crimped is desirably amaterial with high strength & stiffness along with low friction, such asreinforced Nylon. In this respect, the inner crimping wedges 82 may beinserts to the larger jaws 44. Likewise, as mentioned, the cam followers86 are preferably stiff and low friction, such as Nylon. Of course,alternatives exist and these are just exemplary materials.

It will thus be clear that rotation of the cam wheel 62 causes aradially inward motion of the crimping jaws 74 due to the interactionbetween the arcuate cam slots 80 and the cam followers 86. FIGS. 7A and7B are elevational views of the inner crimping mechanism 40 showing thecentral cam wheel 62 and crimping jaws 44 assembled thereon in both openand closed crimping jaw positions. Only one of the arcuate cam slots 80as well as the cooperative cam follower 86 on one of the jaws 44 isshown in phantom. It should be understood that although only one each isshown, there are two cam slots 80 and two cam followers 86 associatedwith each jaw 44. The jaw 44 on which the cam follower 86 is shown ishighlighted by extending dashed lines along respective angled edges toform angles α and β with the horizontal.

FIGS. 7A and 7B show the lever arm 60 of the cam wheel 62 rotating in aclockwise (CW) direction such that the cam followers 86 on each jaw 44are acted on by the arcuate cam slots 80. Because the cam slots 80 curveradially inward as the wheel 62 rotates clockwise, a radially inwardcamming force is transmitted to the cam followers 86. Because of thesliding interactions between the jaws 44, inward movement of all of thejaws 44 from their rigid connection to their respective cam followers 86is the same. It should be noted that the highlighted crimping jaw 44remains in the same rotational orientation while it translates radiallyinward and downward. That is, the angles α and β that describe theorientation of the jaw 44 relative to horizontal remain the same. Thesame is true for all of the jaws 44. As a result of this movement, theinner surfaces of the crimping wedges 82 define a radially constrictingiris 50. Additionally, although the absolute angle of a tangent linedrawn with respect to the curvature of the arcuate slot 80 varies fromone end of the slot to the other, the orientation of the cam follower 86remains parallel to these tangent lines because of the movement of therespective jaw 44. This facilitates sliding movement of the camfollowers 86 within the slots 80.

The crimping jaws 44 have cooperating sliding surfaces such that theyall moved together with the same degree of translation as one another,albeit along different angles. In particular, each of the angular edgesof the traveler blocks 84 cooperates with the adjacent traveler blockedges in a tongue and groove fashion. With reference back to FIGS. 5Aand 5B, each of the traveler blocks 84 has a sliding rail 88 thereonthat mates with an oppositely-oriented sliding rail on the travelerblock 84 on the adjacent jaw 44. This interaction can be seen in theperspective view of FIG. 6 . The sliding engagement of the rails 88helps prevent binding between the jaws 44 as they move inward together.

Furthermore, the starting positions of the crimping jaws 44 and theangles of the edges of the traveler blocks 84 causes the assembly ofjaws to rotate when they are cammed inward. In essence, each of thecrimping jaws slides inward relative to one of its adjacent crimpingjaws, and the resulting displaced shape seen in FIG. 7B somewhatresembles a pinwheel. The reader will also see from comparison of FIGS.7A and 7B where the highlighted crimping jaw 44 translates radiallyinward and downward, amounting to a clockwise rotation thereof.

As seen in FIGS. 5A-5C, the crimping jaws 44 also have linear guideslots 90 on the outer faces of both of the traveler blocks 84. Theseguide slots 90 interact with the aforementioned Cartesian guide elements70, as will be explained below. With specific reference to FIG. 5C, theguide slot 90 of each jaw 44 bisects included jaw angle θ.

FIG. 8 is an elevational view of an inner face of one half of the outerhousing 42 showing the fixed guide channels 64. As mentioned above, theguide channels 64 lie tangent to the central orifice 48 in the housing42. The guide channels 64 preferably comprise axial depressions in anouter plate 92 of the housing 42, with the housing halves including theguide channels desirably being injection molded. Radially inner ends ofeach guide channel 64 merge with an adjacent guide channel at about amid-point thereof. Because there are six guide channels 64 spacedequidistantly and oriented evenly around the orifice 48, the innerportions of the guide channels define vertices of a hexagon closelysurrounding the orifice. Each guide channel 64 extends from a vertex ofthe hexagon past its point of tangency with the orifice 48 and outwardto an outer rim 94 of the housing 48. The guide channels 64 interactwith the Cartesian guide elements 70, as will be explained below. Thenumber of guide channels depends on the number of jaws; namely, half theof number of jaws.

FIG. 9A shows a plurality of the Cartesian guide elements 70 arranged inspace in the same manner as they would be when interacting with theouter housing 42, FIG. 9B shows an individual Cartesian guide element 70in isolation, while FIGS. 10A and 10B superimpose the guide elementsonto the outer housing and channels 64. Each of the guide elements 70comprises an angular generally flat rectilinear plate 96 having a pairof raised linear bars 98 a, 98 b projecting from opposite inner andouter faces. The opposed linear bars 98 a, 98 b are orientedperpendicular to each other, and thus together define a right-anglecross, albeit on opposite faces of the guide elements 70. Outer faces ofthe guide elements 70 abut the outer plate of the housing 42 such thatthe outer linear bars 98 a on that side fit closely within the fixedguide channels 64. On the inner face, the guide elements 70 contact theassembly of the crimping jaws 44, and the inner linear bars 98 b fitclosely within the guide slots 90 on six of the guide elements. Becausethe outer linear bars 98 a are constrained within the guide channel 64,the guide elements 70 are also constrained to move linearly betweenfirst and second positions parallel to the guide channels.

FIG. 10A shows the locations of the guide elements 70 superimposed onthe outer housing 42 when in radially outward positions (as also in FIG.9A). As mentioned, the outer linear bars 98 a extend within and areguided by the guide channels 64. In this starting position, radiallyouter edges of the rectilinear plates 96 are close to the outer rim 94of the housing 42, and their radially inner edges are positioned justoutside of the central orifice 48. FIG. 10B is a similar view showingthe guide elements 70 in radially inward positions. The outer linearbars 98 a slide inward along the guide channels 64, and the rectilinearplates 96 fit closely together. The rectilinear plates 96 define anirregular diamond shape with generally four vertices at the outerextents of the crossed linear bars 98 a, 98 b. Straight sides extendbetween the vertices, and there is an indentation 100 on one sideadjacent one of the vertices. When the guide elements 70 are in theirradially inner positions, one of the vertices of each fits closelywithin this indentation 100 on the next, and the nested contact betweenall of the guide elements 70 in this manner provides a positive stop onfurther inward movement of the crimping mechanism 40.

FIGS. 11A and 11B are elevational views similar to FIGS. 7A and 7B withthe crimping jaw assembly 66 in place but also showing the Cartesianguide members 70 interacting with the crimping jaws 44. The guidemembers 70 are termed “Cartesian” because of the opposite crossed linearbars 98 a, 98 b on each. That is, as described above, the guide member70 are constrained to move linearly along the guide channels 64 in theouter housing 42. At the same time, interaction between the inner linearbars 98 b on each member 70 and the guide slots 90 on every othercrimping jaw 44 constrains those jaws to move in the direction of theassociated guide member 70.

Prior to discussion of this coordinated movement, it should be notedthat there are only six guide members 70, while there are twelvecrimping jaws 44. Therefore, as seen in FIG. 11A, each of the guidemembers 70 interacts with every other crimping jaw 44. The six crimpingjaws 44 a that interact with the guide members 70 can be termed guidedjaws, while the six crimping jaws 44 b that do not interact with theguide members are termed follower jaws. However, it is important toremember that each of the crimping jaws 44 has cam followers 86 thereon,and thus each of the crimping jaws is driven directly by the cam wheel62.

With reference again to FIGS. 11A and 11C, Cartesian axes 102, 104 aresuperimposed over one combination of guide member 70 and its guided jaw44 a. A first axis 102 extends along the outer linear bar 98 a on theguide member 70. The reader will understand that the outer linear bar 98a interacts with the guide channels 64 on the half of the outer housingwhich is not shown. Therefore, the guide member 70 is constrained forlinear movement along the first axis 102. A second axis 104 extendsalong the inner linear bar 98 b on the guide member 70, whichcorresponds to the guide slot 90 on the guided jaw 44 a. The second axis104 translates with the guide member 70, always remaining perpendicularto the first axis 102. Both the guided jaw 44 a and the guide member 70move together. This arrangement reduces frictional losses and allows anoption to combine the guided jaws 44 and the guide elements 70.

Now with respect to FIGS. 11B and 11D, the cam wheel 62 has rotatedclockwise causing sliding movement of all of the crimping jaws 44. Asthe guided jaw 44 a begins to move inward, it is constrained to movealong the first axis 102 with the corresponding guide member 70.Likewise, all of the six guided jaws 44 are constrained to move withtheir corresponding guide members 70. As each guided jaw 44 a starts tomove inward it slides relative to one of the two adjacent follower jaws44 b. Of course, each follower jaw 44 b is acted on by two adjacentguided jaws 44 a. Because of the angled sides of the adjacent jaws 44,as explained above with respect to FIGS. 7A and 7B, the assembly of jawsbegins to rotate clockwise. The circumferential component of movement ofeach of the guided jaws 44 transfers forces via the guide slots 90 tothe inner linear bars 98 b on the guide members 70. This starts theguide members 70 translating along the first axis 102.

It should be mentioned that the provision of two sets of force actuators(disks 72, traveler blocks 84, and guide members 70) results in asymmetric, balanced system and the stresses are reduced. Of course, asingle disk 72 and associated crimping elements is possible, but wouldrequire a more robust structural design.

As the guide members 70 and the guided jaws 44 a translate along thefirst axes 102, they continue to move inward relative to the outerhousing 42. Of course, although they are not directly in contact withthe guide member 70, the follower jaws 44 b move in a like mannerbecause they are also acted on by the cam wheel 62, and from thesymmetry and mating edge contact between the jaws. FIG. 11E isolates acentral one of the guided crimping jaws 44 a from FIGS. 11C and 11D andshows the jaw with its absolute movement 106 along the first axis 102.Continued rotation of the cam wheel 62 eventually moves the crimpingjaws 44 into the positions shown in FIGS. 7B and 11B. It is also worthnoting that the tip of the crimping wedge 82 on each jaw translatesradially inward along a radial line 110 through the central crimpingaxis 46 (see FIG. 11A). That is, the composite movement 106 is parallelto the radial line 110 through the crimper axis 46. This ensures evencrimping of the stent or valve.

The relative movements of the cooperating elements in the crimpingmechanism 40 will occur regardless if there is an object being crimpedor not. However, when an object such as the expanded heart valve 20 ofFIG. 1A is being crimped, it applies substantial resistance to thecrimping mechanism 40. More specifically, the hoop strength of theexpanded heart valve 20 provides a radially outward reaction force 108directly to the crimping wedges 82 of the jaws 44, as indicated in FIG.11E.

Without the guide members 70, the mechanism is not balanced and thereaction force 108 will tend to rotate the jaws 44. Further, without theguide members 70 this reaction force would be translated through thecrimping jaws 44 to the cam followers 86, and thus to the arcuate camslots 80 of the cam wheel 62. Although the cam slots 80 are relativelyrobust, the cam followers 86 are not only susceptible to deformationfrom stress, but also binding. However, because of the contact betweenthe guide members 70, crimping jaws 44 and fixed outer housing 42, thereaction forces from the crimping process are transferred anddistributed such that the stress on the cam followers 86 is reduced. Inparticular, the Cartesian guide members 70 absorb a considerable amountof the stress and provide an effective companion for the crimping jaws44. With respect to FIG. 11E, the radially outward reaction force 108from the crimping process translates into a torque on the crimping jaw44 a. This torque is resisted primarily by the rigid constraint imposedon the guide member 70 by the outer housing guide channels 64 to movealong the first axis 102. To be more explicit, the clockwise torque onthe guided jaw 44 a would be translated directly to the correspondingguide member 70 because of the interaction between the guide slot 90 andthe inner linear bar 98 b, and the rotational torque will then beresisted by the guide member 70 because it is fixed rotationally withrespect to the outer housing 42.

One benefit over previous crimpers is in the smaller mechanism size (˜½the size of current crimpers) and in the ability to operate under highcrimping forces (small and stiff crimping jaws). The jaws 44 aredisplaced essentially radially using the Cartesian guiding element 70positioned close to the central orifice 46. This guided concept enablesdramatic reduction of the size of the crimping jaws 44 and the stiffness(or the ability to withstand higher crimping forces) of the jaws isincreased. The radial alignment mechanism provided by the guidingelements 70 is based on steep angular movement translated to radialforces imposed close to the central crimping axis. The guiding elements70 translate the angular movement from the cam wheel 62 to a radialforce, by essentially separating it into a Cartesian movement. In thismovement, the jaws 44 are moving radially similarly to the previouscrimpers, and the guiding elements 70 move with them, in the tangentialhousing channels 64.

In a preferred embodiment, the width of the crimping mechanism 40, orapproximately the diameter of the cam wheel 62, is about 80 mm. A totalheight of the crimping mechanism 40, such as shown in FIG. 2A whichincludes the cam wheel 62 above the lead screw 52 and associatedactuators, is about 115 mm. Of course, those exemplary sizes are for amechanism capable of crimping a balloon-expandable prosthetic heartvalve 20 such as shown in FIG. 1A down to a delivery size shown in FIG.1B. The mechanism must be robust enough to crimp a stainless steelsupport frame of the heart valve 20 from, for example, 30 mm (D_(max))down to 6 mm (D_(min)). Less stiff frames or less of a size reductionmay enable the crimper to be even further reduced in size and,conversely, a larger size reduction may require a larger crimper.

FIGS. 12A and 12B are schematic perspective views of an alternativeembodiment of a crimping mechanism 120 in both open and closed positionsof crimping jaws 122, respectively. The entire crimping mechanism 120 isnot shown, but will be similar to that shown in FIGS. 1-11 . The maindifference in the crimping mechanism 120 is a modification to the guidemembers 124. That is, rather than having a diamond-shape plate withopposing crossed linear bars, as before, the guide members 124 aresimply perpendicular bars attached together. The inner bars will extendwithin guide slots 126 in the crimping jaws 122, while the outer barswill slide within fixed guide channels in an outer housing (not shown).In all other respects, the crimping mechanism 120 works the same as wasdescribed above.

FIGS. 13A-13C and 14A-14C illustrate a further crimping mechanism 140similar to that shown in FIGS. 1A-12B but with fewer guide elements 142.The guide elements 142 are simple crossed linear bars, as describedabove with respect to FIGS. 12A and 12B. Further, there are still twelvecrimping jaws 144. In contrast to the earlier embodiments, however,there are only two guide elements 142. Operation of the crimpingmechanism 140 as seen in FIGS. 14A-14C is similar to that describedabove, where a lead screw 146 turns a cam wheel (not shown) whichinitiates the inward movement of the crimping jaws 144. Because thecrimping jaws 144 are all linked in a tongue and groove fashion as wasdescribed above, they would move in sync in and out even without guideelements 142. The guide elements 142 only mesh with two of the crimpingjaws 144, but still provide a reduction in stress and distributedapplication of force. Two guide elements 142 is considered a minimum,and three, four, or six are contemplated for a twelve jaw mechanism. Apractical maximum number of guide elements 142 is six in the illustratedembodiments, or half the number of jaws. This is so that the guideelements 142 do not interfere with each other as they slide back andforth.

FIGS. 15A-15B schematically depict a still further crimping mechanism160 of the present application that utilizes a compressible sleeve, suchas a soft elastomer, rather than a plurality of separate jaws. FIGS.16A-16B are elevational views of the crimping mechanism 160 with a frontcover removed to show internal components in the positions of FIGS. 15Aand 15B, respectively. The crimping mechanism 160 features a cam wheel162 that rotates within a pair of end plates 164 (only one shown). Theend plates 164 are fixed over a housing 166 within which is located anactuation mechanism, much like the lead screw assembly described above.

A compressible sleeve 168 is held rotationally still between the endplates 164 and comprises an annular elastomeric sleeve with outer axialgrooves. An inner lumen or orifice 170 defined by the sleeve 168constricts upon rotation of the cam wheel 162 to a smaller size orifice170′, as seen in FIGS. 15B and 16B.

With reference to FIGS. 16A-16B, as well as to FIGS. 17-19B, a pluralityof linkage plates 172 are arranged for coordinated movement within thecam wheel 162. More particularly, outer ends 174 of the plates 172 arejournaled for rotation in corresponding bores 180 around the outerperimeter of the cam wheel 162. The cam wheel 162 may have a shortsegment of gear teeth 176 on its lower edge which can be engaged by amoving rack, lead screw or other such gearing within the housing 166.

FIG. 17 shows the crimping mechanism 160 exploded. An array 182 of thelinkage plates 172 and cooperating compression plates 178 (see FIGS.19A-19B) includes at least 12, and preferably at least 24 of the linkedplates. The array 182 is arranged within the cam wheel 162 whichincludes two series of the perimeter bores 180 within which two outerends 174 of each linkage plate 172 are journaled for rotation. In thisway, the symmetry reduces any possible misalignment forces duringcrimping of the prosthetic heart valve. Each end plate 164 has a centralaperture for passage of the prosthetic heart valve into the middle ofthe crimping mechanism 160, as well as an array of radial slots 186which will be described below.

As seen best in the cutaway views of FIGS. 19A-19B, each linkage plate172 is hinged on an inner end to a compression plate 178. The inner endof each compression plate 178 engages one of the axially-orientedgrooves 179 around the outside of the compressible sleeve 168. Thecompression plate 178 is formed with two outer rails 188 that slidewithin the radial slots 186 formed in the end plates 164. Rotation ofthe cam wheel 162 displaces the outer ends 174 of the linkage plates 172such that they transition from the angled orientation shown in FIG. 16Ato the radial orientation of FIG. 16B. Because the inner ends of thelinkage plates 172 are hinged to the compression plates 178, thecompression plates 178 are forced radially inward. Engagement betweenthe outer rails 188 and the slots 186 constrains the compression plates178 for radial movement. The linked plates 172, 178 surrounding thesleeve 168 thus push inward on the grooves 179 and compress the sleeveradially to reduce the central orifice diameter.

Although the crimping mechanism 160 represents an elegant solution, witha single crimping “jaw” reducing the number of moving parts andassociated friction, there are limitations on the magnitude of crimping,and a series of similar crimpers may be required to reduce the size ofthe article in stages. Of course, if only a small amount of crimping isnecessary, one crimping mechanism will be suitable.

FIGS. 20A-20C are perspective and cutaway views of a multi-stage crimper200 with an outer housing 202 enclosing a series of progressively sizedcrimping mechanisms 204 a, 204 b, 204 c each with a compressible “jaw.”A crimping orifice 206 a, 206 b, 206 c for the three crimping mechanismsgradually reduces the size of a prosthetic device such as the prostheticheart valve described above. FIG. 20B shows a front cover of the housing202 removed to illustrate one rotating cam wheel 210 on the smallestcrimping mechanism 204 a. A lower segment of gear teeth 212 on the camwheel 210 may be acted on by a linearly displaced rack 214 to rotate thecam wheel. Although not shown, the larger crimping mechanisms may alsohave similar cam wheels which are acted on simultaneously by the singlerack 214. FIG. 20C shows a front portion of the cam wheel 210 removed toexpose a plurality of linked plates 216, which may be the same as thosedescribed above with respect to FIGS. 15-19 .

To crimp a prosthesis, it is first placed in the largest crimpingmechanism 204 c and the rack 214 displaced to reduce the size of theprosthesis a first amount. The rack 214 returns to its original positionand the prosthesis is then transferred to the middle crimping mechanism204 b and its size is further reduced. Finally, the smallest crimpingmechanism 204 a reduces the size of the prosthesis to its finaldiameter. Although three crimping mechanisms are shown, a minimum of twostages and more than three may be used for sequentially crimping aprosthesis in this manner.

FIGS. 21A-21B schematically depict a still further crimping mechanism ofthe present application that utilizes compressible jaws 260, such as asoft elastomer. The jaws 260 are positioned between a series ofspoke-like plates 262 which are initially angled from the radial so asto be nearly tangential to a circle defined by the inner faces 264 ofeach of the compressible jaws 260. Outer faces 266 of each of the jaws260 are constrained so that they cannot expand radially outward. Byrotating all of the spoke-like plates 262 together, as seen in FIG. 21B,the compressible jaws 260 are squeezed by reduction in the volumebetween the plates 262 so that they expand inward. The aggregation ofall of the interfaces 264 defines the crimping iris, and compresses anyarticle therewithin. Again, with compressible jaws there are limitationson the magnitude of crimping, and a series of similar crimpers may beused to reduce the size of the article in stages, as described abovewith respect to FIGS. 20A-20C. Of course, if only a small amount ofcrimping is necessary, a single crimping mechanism will be suitable.

It should be understood that internal components of the crimpingmechanisms described herein may be formed of multiple separate connectedparts, or by combining some of these parts in integral members. Forexample, the six guided jaws 44 seen in FIGS. 11A and 11B areconstrained to move with their corresponding guide members 70, and thusthese components could be formed as single pieces. To the contrary,certain elements can be broken up into more than one piece, such as thejaws, so as to facilitate manufacturing. This latter instance isillustrated by the crimping mechanism shown in FIGS. 22A-22C.

FIG. 22A is a perspective view of an alternative crimping mechanism 300having a modified actuating mechanism and an outer housing 302 shown inphantom. FIG. 22B shows the crimping mechanism 300 from a differentperspective and without the outer housing 302, and FIG. 22C shows anumber of internal components including inner crimping wedges 306exploded.

The modified actuating mechanism again features a relatively largediameter horizontally oriented lead screw 310 journaled for rotation oneither side of the housing 302 and perpendicular to a horizontalcrimping axis. A motor 312 in the lower part of the housing 302 isdesirably connected via a power transmission (e.g., gears or pulleys314) to drive the lead screw 310. In contrast with the actuatingmechanism described above with respect to FIGS. 2A-2B, rotation of thelead screw 310 causes translation of a carriage assembly 316 which isconnected to a cam wheel 318 via a linkage arm 320. That is, the linkagearm 320 is journaled for rotation at opposite ends, one on the carriageassembly 316 and one on an outer lever arm 322 of the cam wheel 318. Aswith the earlier embodiment, the cam wheel 318 has two spaced apartdiscs 324 each with a lever arm 322, and there are two of the linkagearms 320, one driving each lever arm. This provides an extremelybalanced and robust drive system which prevents binding of the movingjaw components.

This linkage arrangement provides an extended actuation arm thatproduces higher torque (linear translated to radial) results at the endof crimping process, where the maximal forces are needed. In otherwords, the stented prosthetic valve is easier to crimp at it largerdiameter, and becomes progressively harder as it is constricted. As thecarriage assembly 316 reaches the end of the lead screw 310, the linkagearms 320 apply a large amount of torque to the cam wheels 318 relativeto each turn of the lead screw.

FIG. 22C is an exploded view of the components of the assembly of thecam wheel 318 and jaw mechanism. The crimping wedges 306 are shownarranged in a generally spiral array as they would be held within acentral opening 330 in the cam wheel 318. The crimping wedges 306 takethe place of the inner crimping wedges 82 of the jaws 44 described abovewith reference to FIGS. 1A-11E. Flanking each side of the cam wheel 318is a combination of a set of six generally triangular (pie-shaped)traveler blocks 332 and six guide blocks 334. The guide blocks 334include essentially two components back-to-back: inner traveler blocks336 that resemble the traveler blocks 332 and outer guide elements 338that are similar to the Cartesian guide elements 70 described above. Asseen in FIG. 22B, the six traveler blocks 332 and six guide blocks 334mesh in the same manner as the jaws 44 of FIGS. 1A-11E. The guideelements 338 have linear bars 340 that slide within fixed guide channels(not shown) in the inner faces of the housing 302. Each of thepie-shaped traveler blocks 332, 336 mesh with adjacent blocks in atongue-in-groove fashion to enable smooth sliding movement therebetween.

A crimping jaw assembly of the crimping wedges 306, six traveler blocks332 and six guide blocks 334 is formed via a plurality of alignedthrough bores and bolts 342. As in the earlier version, spiral cam slots350 in the cam wheel 318 move small cam pins 352 inward as the wheelrotates. The cam pins are held within bores (not shown) on the innerfaces of each of the six traveler blocks 332 and six guide blocks 334 sothat the blocks are forced along linear paths as constrained by thelinear bars 340 sliding within fixed guide channels of the housing 302.This is the same as was described above. The end result is that theinner tips of the crimping wedges 306 translate inward along radiallines to evenly crimp a stented valve therewithin.

Each crimping jaw, per se, includes an assembly of one of the crimpingwedges 306 connected at both axial ends to a pair of either the travelerblocks 332 or the guide blocks 334. As can be appreciated, the severalcomponents may be manufactured separately of the same or differentmaterials and then secured together across and through the cam wheel 318via the bolts 342. Preferably, the crimping wedges 306 are formed of arelatively rigid metal, or just inner tips of the crimping wedges 306may be metal. The sliding pieces may be metal or a hard plastic orresin.

The combination of previously separate parts to form the six guideblocks 334 illustrates the option of using fewer more complicated parts,while the exploded assembly of FIG. 22C shows the option of using more,less complex parts. Ultimately, the choice of which configurationdepends on materials, mold cost, engineering difficulty, etc. In apreferred embodiment, an assembly including a wedge 306 plus either twotraveler blocks 332 or two guide blocks 334 is formed as one piece,preferably defining twelve jaw assemblies.

Exemplary embodiments of the invention have been described, but theinvention is not limited to these embodiments. Various modifications maybe made within the scope without departing from the subject matter ofthe invention read on the appended claims, the description of theinvention, and the accompanying drawings.

What is claimed is:
 1. A prosthetic valve crimping device capable ofreducing the diameter of an expandable prosthetic heart valve,comprising: a plurality of crimping jaws in meshing engagement andcircumferentially arranged around a central crimping axis, each crimpingjaw having radially inner crimping wedges defining a crimping orificeand radially outer ends with two spaced apart cam followers; astationary outer housing containing the crimping jaws; first and secondcam wheels mounted to rotate within and being rotatable relative to thehousing, each cam wheel having a plurality of arcuate cam slots thatreceive the cam followers, with each cam slot in the first cam wheelbeing identically radially and circumferentially positioned as amatching one of the cam slots in the second cam wheel and the matchingcam slots receiving the two spaced apart cam followers in one of thecrimping jaws; and a plurality of linear guide channels formed in theouter housing, wherein the crimping jaws are constrained by the guidechannels such that rotation of the cam wheel causes the cam slots to acton the cam followers and displace the crimping wedges of the crimpingjaws along radial lines toward the crimping axis and reduce the size ofthe crimping orifice, wherein a prosthetic heart valve may be positionedwithin the crimping orifice and acted on by the combined crimping wedgesto reducing the diameter of the prosthetic heart valve.
 2. The device ofclaim 1, wherein the crimping wedges are made of a different materialthan the rest of the crimping jaws.
 3. The device of claim 1, furtherincluding a plurality of guide elements positioned between the pluralityof crimping jaws and the outer housing, the guide elements beingconstrained by the guide channels in the outer housing for movementbetween first and second positions along tangential lines that aretangential to a circle around the central axis.
 4. The device of claim3, wherein at least some of the guide elements are rigidly coupled toassociated ones of the crimping jaws.
 5. The device of claim 1, whereinthe crimping jaws each comprise an assembly of a pair of travelingblocks flanking the first and second cam wheels and one of the crimpingwedges that extends across aligned central orifices in the first andsecond cam wheels.
 6. The device of claim 5, wherein the cam followersextend axially inward into the cam slots.
 7. The device of claim 1,wherein the first and second cam wheels each have a cam lever projectingradially outward therefrom that is driven by a lead screw mounted to thehousing.
 8. The device of claim 7, further including a carriage assemblyarranged to travel along the lead screw, and a linkage between the camlevers and the carriage assembly that increases a torque applied to thecam wheel when the carriage assembly reaches opposite ends of the leadscrew.
 9. The device of claim 7, further including a drive motor foractuating the lead screw.
 10. The device of claim 1, wherein there areexactly twelve crimping jaws.
 11. The device of claim 1, wherein thecrimping device is capable of reducing the diameter of an expandableprosthetic heart valve from around 30 mm in diameter down to at least 6mm in diameter, and the crimping device has a compact size with adiameter of the first and second cam wheels being about 80 mm.
 12. Aprosthetic valve crimping device capable of reducing the diameter of anexpandable prosthetic stented valve, comprising: a plurality of crimpingjaws in meshing engagement and circumferentially arranged around acentral crimping axis, each crimping jaw having radially inner crimpingwedges defining a crimping orifice and radially outer ends with twospaced apart cam followers; a stationary outer housing containing thecrimping jaws; and first and second cam wheels mounted to rotate withinand being rotatable relative to the housing, each cam wheel having aplurality of arcuate cam slots that receive the cam followers, with eachcam slot in the first cam wheel being identically radially andcircumferentially positioned as a matching one of the cam slots in thesecond cam wheel and the matching cam slots receiving the two spacedapart cam followers in one of the crimping jaws, wherein the crimpingjaws are constrained by the outer housing such that rotation of the camwheel causes the cam slots to act on the cam followers and displace thecrimping wedges of the crimping jaws along radial lines toward thecrimping axis and reduce the size of the crimping orifice, wherein thefirst and second cam wheels each have a cam lever projecting radiallyoutward therefrom that is driven by a lead screw mounted to the housing.13. The device of claim 12, further including a plurality of guideelements positioned between the plurality of crimping jaws and the outerhousing, the guide elements being constrained by guide channels in theouter housing for movement between first and second positions alongtangential lines that are tangential to a circle around the centralaxis.
 14. The device of claim 13, wherein when the guide elements aredisplaced to the second positions along the lines, one nesting portionof each guide element fits closely against a structural feature on anadjacent guide member, and a nested contact between all of the guideelements in this manner provides a positive stop on further inwardmovement of the crimping mechanism.
 15. The device of claim 13, whereinthere are half the number of guide elements as crimping jaws, such thatsome of the crimping jaws are driven and some are followers.
 16. Thedevice of claim 12, wherein the crimping jaws each comprise an assemblyof a pair of traveling blocks flanking the first and second cam wheelsand one of the crimping wedges that extends across aligned centralorifices in the first and second cam wheels.
 17. The device of claim 15,wherein the cam followers extend axially inward into the cam slots. 18.The device of claim 12, further including a drive motor for poweredactuation of the lead screw.
 19. The device of claim 12, furtherincluding a crank for manually actuating the lead screw.
 20. The deviceof claim 12, wherein the crimping device is capable of reducing thediameter of an expandable prosthetic heart valve from around 30 mm indiameter down to at least 6 mm in diameter, and the crimping device hasa compact size with a diameter of the first and second cam wheels beingabout 80 mm.